Solvent refining of hydrocarbon oil



Patented Nov. 12, 1935 SOLVENT REFININgIBF HYDROC'ARBON Louis A. Clarke,FishkilL N. Y., assignor to The Texas Company, New York, N. Y., acorporation of Delaware No Drawing.

Application November 3, 1933,

Serial No. 696,541

2 Claims.

This invention relates to refining hydrocarbon oil, and moreparticularly to refining mineral oil by solvent extraction.

The invention contemplates the treatment and refining of mineral oilwith a selective solvent whereby the oil is separated into fractionshaving desired characteristics.

The invention has particular reference to the extractive treatment ofmineral oil with a solvent selected from the low-boiling members of thealkyl acyl derivatives of furan, such as acetyl,

propionyl and butyryl furan. 2-acetyl furan, for

example, has the following chemical structure:

The foregoing solvent liquids are suitable for extracting undesiredconstituents from mineral oils, and particularly from lubricating oilfractions.

Lubricating oils, such as produced from midcontinent crude, areordinarily composed of relatively parafiinic constituents, and alsorelatively non-paraffinic constituents, including naphthenic, aromatic,and unsaturated hydrocarbon bodies. The solvent of my invention isadapted to extract these relatively non-paraninic bodies from the oilfor the production of lubricating oil fractions which are of relativelyhigh parafli'nic character, and therefore of relatively higher viscosityindex than the untreated oil.

In the application of my invention to the treatment of mineral oils forthe production of lubricating oil, one part of the oil is mixed withabout two parts of solvent liquid, and this mixture is then subject toagitation and heating in order to effect solution of the undesiredconstituents of the oil in the solvent. The extent to which the oil issoluble in the solvent will depend upon the nature of the oil as well'asupon the condition of temperature and pressure employed. The conditionsof temperature and pressure, as well as the ratio of solvent to oil, maybe varied for the purpose of effecting the particular degree ofextraction desired. The temperatures employed, for example, may rangefrom about 0 F. to 200 F. or thereabouts.

Upon settling, the mixture separates into two layers, one of whichcomprises the constituents which it is desired to extract from the oildissolved in the bulk of the solvent liquid, while the other layercomprises the undissolved and. relatively parafiinic oil in admixturewith a relatively small amount of solvent.

The two layers are then separately withdrawn, and the solvent liquidrecovered therefrom. If desired, the separated layers may be subjected 5to treatment with additional quantities of the solvent for the purposeof obtaining a series of fractions of differing characteristics.

In order to illustrate the invention, the following specific example isgiven in which an oil, 10 derived from mid-continent crude, wasextracted with acetyl furan at atmospheric pressure.

The acetyl furan used comprised aproduct with a boiling point of from338 to 348 F. produced by reacting furoic and acetic acids over 15manganous oxide at about 750 F. This material was liquid at roomtemperature.

This solvent was mixed with the oil to be extracted in the proportion ofone part of solvent compound to one part of oil, and while main- 20tained at a temperature of about 75 F., the mixture was permitted toseparate into two layers. The resulting raflinate, or substantiallyinsoluble portion of theoil, comprised about 87% of the original oil.The viscosity and viscosity in- 5 dex of the untreated oil and theresulting railinate were as follows:

Untrsmted Raflinate 30 Saybolt universal viscosity at 210 F... 80. 5 74Viscosity index 51 In some instances, it may be of advantage to carryout the extraction in the presence of a modifying solvent liquid, suchas benzol, or a light petroleum naphtha, or a petroleum fractioncomposed of propane or other similar low boiling 40 hydrocarbons, forthe purpose of facilitating the extraction and further controlling theextent thereof.

The lubricating oil distillate may be subjected to the foregoingextraction treatment, either be- 45 fore or after dewaxing, orsubsequent to treatment with other solvents or chemicals.

The invention is not necessarily limited to the treatment of lubricatingoil fractions, since the solvent may be adapted to the refining andpuri- 50 fication of various hydrocarbon or mineral oil fractions,including naphtha, cracked naphtha, kerosene, etc., as well as residualor distillate fractions, or products derived from petroleum or othersources. as

By reference to the acyl derivatives of furan in the foregoingspecification and in the appended claims, it is intended to include theisomers in each instance since each species may consist of a mixture ofits isomers.

non-parafiinic constituents, including naphthenic, aromatic, andunsaturated bodies, to remove undesired relatively non-parafiinicconstituents therefrom, which comprises extractively treatingthe oilwith a relatively low boiling member of the series of compoundscomprising the aliphatic acyl derivatives of furan of the character ofacetyl furan whereby the undesired constituents are separated from theoil as an extract soluble in the solvent liquid.

2. The method of refining hydrocarbon oil containing relativelyparafiinic and relatively non-paraifinic constituents, includingnaphthen- 1 ic, aromatic, and unsaturated bodies, to remove undesiredrelatively non-paraflinic constituents therefrom, which comprisesextractively treating the oil with a solvent comprising acetyl furanwhereby the undesired constituents are separated from the oil as anextract soluble in the solvent liquid.

,- LOUIS A. CLARKE.

